The present invention concerns adhesive dressings and in particular dressings having an adhesive surface for adhering to the skin of a patient.
Adhesive dressings and devices are well known in the art for use as wound coverings, device fixation and other health applications. Specific applications of such adhesive dressings may be found in the area of wound dressings, drug delivery, finger bandages, urinary catheters and ostomy sealing materials. It is generally known to combine adhesives with an occlusive film, cloth or foam outer backing layer to protect and aid in the removal of the adhesive device. For instance, U.S. Pat. No. 3,339,546 discloses a bandage which comprises a waterproof film of a material such as polyethylene, and a water absorbent hydrocolloid adhesive, with the adhesive mass firmly attached to the backing. Numerous other patents disclose various compositions for absorbent adhesives containing mixtures of a sticky elastomer, such as polyisobutylene, and mixtures of hydrocolloid gums, such as pectin, carboxymethylcellulose, karaya and other tackifiers and plasticizers. See, e.g., U.S. Pat. Nos. 4,813,942 and 6,326,421.
In general, prior devices utilize an occlusive film, foam or laminations of similar materials that form an attached outer backing to protect the adhesive and serve as an upper support means for strengthening the weak adhesive mass, as well as to facilitate removal after use. Certain formulations are known for fluid absorptive adhesives that will attach a collector housing to a body surface for covering wounds. Removal of these devices is accomplished by pulling a flexible film backing attached to the adhesive layer.
Although widely used, human skin adhesives have relatively low cohesive strength. Since absorptive adhesives are filled with water absorbent particles, they lose even more cohesive strength in use as the particles swell while absorbing moisture from the skin and other body fluids. Cohesive failure of the adhesive in a wound covering may become a significant problem requiring constant attention in case the dressing becomes compromised. This problem is further exacerbated when absorptive adhesive dressings leave residue or gel-like material behind on sensitive skin areas or in a wound.
No prior adhesive devices have adequately addressed the removal problems associated with such adhesives. Removal of the prior devices requires that the edge of the adhesive layer or dressing be lifted, usually by scratching with a fingernail, to pull off the combined backing layers and adhesive mass. This frequently results in adhesive left on the patient's skin, on the fingers or gloves of the medical personnel, and/or within the wound bed. Cleaning this residue with solvents is often required, which may lead to further irritation or injury.